International Career

Krasnykh made his senior international debut at the short course World Championships in 2014. A year later he was in front of a home crowd at the World Championships in Russia, where he finished 7th in the 200 meter freestyle in 1:46.88.

2016 Rio Olympic Games

In his Olympic debut, Krasnykh made the final in the 200 meter freestyle where he finished 8th in 1:45.91. He also swam the 400 meter freestyle where he finished 15th overall in 3:47.39. Krasnykh joined his Russian teammates in the 800 meter freestyle relay, finishing 5th in the final.

2017 World Championships

On day three at the World Championships, Krasnykh won the bronze medal in the 200 meter freestyle behind Sun Yang of China and Townley Haas of the USA. He touched in a new best time of 1:45.23. He also swam the 400 meter freestyle to begin his meet setting a new best time of 3:47.35 but failing to make the final, finishing in 13th.

He was back in action in the 4×200 meter freestyle relay where he was joined by Mikhail Dovgalyuk, Mikhail Vekovishchev and Danila Izotov to win the silver medal. Krasnykh swam the final leg to move Russia past USA but James Guy of Great Britain over took both teams to take the gold. Krasnykh had a final split of 1:44.80 to help Russia to finish in 7:02.68.